#! /usr/bin/env python
# -*- coding: utf-8 -*-
# vim:fenc=utf-8
#
# Copyright © 2018 crane <crane@crane-pc>
#
# Distributed under terms of the MIT license.

"""

"""

# X ~ N(ax + b)

def test():
    # ax + b < t (a>0)
    # ===> ax < t-b  ====> x < (t-b)/a
    a = 2
    b = 3
    t = 8
    # t = 2

    mean = a * 0 + b
    sd   = a * 1

    # 两个值一模一样, 有待证明(awesome)
    x_exact = (t-b) / a
    x_z_score_approx = (t - mean) / sd      # z-score: 根据mean和sd公式 ===> (t - b) / a

    print(x_exact)
    print(x_z_score_approx)


def main():
    print("start main")
    test()

if __name__ == "__main__":
    main()
